Assessment and suitability of DUS traits to screen potato (Solanum tuberosum L.) genotypes for Phytophthora spp. infection resistance by using phenotypic and molecular (SSR) markers

The present investigation aimed to identify reliable morphological markers that could serve as indicators for Phytophthora infestans Mont. resistance in potato germplasm. A total of 86 potato genotypes were subjected to genetic diversity assessment using simple sequence repeats, followed by a field trial alongside to evaluate resistance responses and morphological characteristics. Two genotypes (LA CHIPPER and J/95–144) exhibited high resistance to late blight (LB), while four genotypes (BR 6609–7, NO–NOVA, MP/99–406, and CP–4174) displayed moderate resistance. The disease response was juxtaposed DUS characters, thus leading to the identification of critical traits (semi-compact to compact foliage, solid stem, angular stem cross-section, no secondary stem coloration, anthocyanin pigmentation on the stem, smooth tuber skin, and white to creamy tuber flesh coloration). These DUS parameters could be utilized for developing high-yielding, LB-resistant potato cultivars in future breeding programs.